1. Field of the Invention
The present invention relates to an endoscope including an inserting portion with a thin diameter and an operating portion having therein an electric device such as an image pick-up unit.
2. Description of the Related Art
In recent years, an endoscope has widely been used in medical and industrial fields. Further, an endoscope is commonly used, having therein an image pick-up unit incorporating an image pick-up device which simply records an endoscope image obtained by the endoscope and easily edits and reuses it.
A micro-sized image pick-up device is developed. In the case of an endoscope having an inserting portion with a thin diameter for the bronchi, the image pick-up device is mounted at the distal end portion of the inserting portion and then the outer diameter of the inserting portion is larger.
Therefore, an endoscope having an image pick-up device in an operating portion is disclosed. For example, Japanese Unexamined Patent Application Publication No. 11-23983 (hereinafter, referred to as a document 1) discloses the above-mentioned endoscope as a well-known art.
According to the well-known art disclosed in the document 1, the operating portion has the image pick-up device near at the proximal end thereof, and an optical fiber is inserted in the inserting portion so as to transmit an optical image to the proximal end of the optical fiber at which the image pick-up device is mounted. The optical image of a subject is formed onto the image pick-up device via an image pick-up optical system mounted facing the proximal end of the optical fiber. According to the document 1, the proximal end of the optical fiber and an image pick-up unit (TV camera) are incorporated in the operating portion on the back side of a portion branched to a universal cord.
Further, a well-known art disclosed in Japanese Unexamined Patent Application Publication No. 11-151200 (hereinafter, referred to as a document 2) discloses an endoscope in which an optical image of a subject is formed onto an image pick-up surface of an image pick-up device in a grip portion having the proximal end of an optical fiber for transmitting an image, which is inserted in an inserting portion to be inserted into the eyeball.
According to the document 2, the optical fiber inserted in the inserting portion is mounted so that it is extended substantially straight in the grip portion, and the optical image of the subject is formed onto the image pick-up device via a projecting lens facing the optical fiber.
In the case of a so-called soft endoscope having a soft inserting portion and a hard endoscope having a hard inserting portion, the endoscope having a mechanism for bending the distal end portion of the inserting portion includes an optical fiber for transmitting the image which is generally designed with flexure in consideration of the following points.
Upon bending the inserting portion or distal end portion of the optical fiber, the excessive stretch and the resultant damage of the optical fiber is prevented.
The variation in length of the optical fiber or the inserting portion is absorbed.
A channel tube for absorbing and supplying air and solution, or a wire for bending is avoided.
The optical fiber upon assembly is easily attached.